In many cities the utilities are located beneath the surface of the earth, usually beneath the surface of the streets. These utilities are placed in tunnels or conduits. In the older cities, such as New York City, these utilities have been located in conduits for years or even decades. Over time the conduits which carry utilities may wear out and break. Further, electrical lines may simply be used beyond their use life as higher electrical loads are placed upon the lines. A serious problem is the failure of electrical transmission lines. These failures usually result in fires which must be quickly extinguished to prevent damage to the surrounding infrastructure.
While it is desirable to replace very old utilities in conduits and tunnels, it is not always practical. Due to financial restraints and other limitations, most of these electrical transmission lines have not been replaced. Unfortunately, failure of older electrical transmission lines can result in an electrical fire. These fires are commonly discovered when smoke is seen arising from manhole covers in the streets and sidewalks. It has been estimated by Consolidated Edison that there are approximately 40 electrical fires per day under the streets of New York City.
The cost of repairing and replacing the electrical transmission lines damaged by these fires is approximately $100,000.00 per linear foot of transmission line. Therefore, it is imperative that these fires be extinguished as quickly as possible. Inspection of lines can help pinpoint potential trouble areas. Unfortunately, inspection of the lines can trigger a fire. For instance, the opening of a manhole cover can provide the oxygen needed to support a fire. Similarly, a lineman performing an inspection may disturb a conduit resulting in arcing of electric lines, possibly triggering a fire.
Normally a lineman inspecting a potential problem area occurs while electrical power is still flowing through the lines. The inspection takes place within the manhole wherein a lineman inserts himself into the manhole. Typically a ladder is placed through the manhole and the lineman climbs down the ladder to permit inspection from within. Unfortunately the lineman can trigger a fire, or simply be in the wrong place at the wrong time. There have been many instances where a fire begins while the lineman is on the ladder. For instance, a fire may be smoldering as evidence by smoke coming out of the manhole. A lineman or fireman may then enter the manhole, and without notice, the smoldering may burst into an all encompassing fire. In many such instances, the individual who climbed into the manhole is now at risk of injury or death.
Another area of concern is the use of ladders for extracting people from burning buildings. Firemen do not hesitate to lean a ladder against a building to reach the lower floors in an effort to fight fires or extract survivors. Unfortunately such a situation cannot predict if a fire will erupt from a lower floor and engulf the firefighter while he/she is on the ladder. While the firefighter is likely prepared for a flash fire and is appropriately dressed, any survivor that they are pulling down the ladder will not be dressed should a fire approach the ladder area.
U.S. Pat. No. 6,834,728 discloses a system for extinguishing a fire in a tunnel. The system includes a conduit for delivering a fire extinguishing liquid and a trough extending parallel to the conduit for receiving liquid from the conduit. A carriage is arranged to move on a track which includes an upper edge of the trough. The carriage carries a pump having a nozzle, a video camera, and an inlet; each of which can be controlled robotically from a remote control station.
U.S. Pat. No. 7,096,965 discloses a method of proportioning a foam concentrate into a non-flammable liquid to form a foam concentrate/liquid mixture and create a flowing stream of the foam concentrate/liquid mixture. Nitrogen is introduced into the stream of the foam/liquid mixture to initiate the formation of a nitrogen expanded foam fire suppressant. The flowing stream carrying the nitrogen expanded foam is dispensed, which completes the full expansion of the nitrogen expanded foam fire suppressant, into the confined area involved in the fire, thereby smothering the fire and substantially closing off contact between combustible material involved in the fire and the atmosphere.
U.S. Pat. Nos. 7,096,965 and 7,104,336 disclose a method and apparatus for proportioning a foam concentrate into a non-flammable liquid to form a foam concentrate/liquid mixture.
U.S. Pat. No. 7,124,834 discloses a method for extinguishing a fire in a space such as a tunnel. The method includes spraying a fire extinguishing medium into the space by spray heads. In a first stage of the method, the flow and temperature of the hot gases produced by the fire are influenced by spraying an extinguishing medium into the space, especially by creating in the space at least one curtain of extinguishing medium.
U.S. Patent Publication No. 2008/0035354 is entitled “Water Based Fire Extinguishers”, the contents of which are incorporated herein by reference, discloses a process for retarding or extinguishing conflagrations using a super absorbent polymer in water. The reaction of the water with the polymer creates a viscosity that can be readily pumped through a standard water based fire extinguisher, yet viscous enough to cover vertical and horizontal surfaces to act as a barrier to prevent fire from damaging such structures.
U.S. Pat. No. 7,169,843 discloses absorptive, cross-linked polymers which are based on partly neutralized, monoethylenically unsaturated monomers carrying acid groups, and with improved properties, which has a high gel bed permeability and high centrifuge retention capacity.
U.S. Pat. No. 5,989,446 discloses a water additive for use in fire extinguishing and prevention. The additive comprises a cross-linked water-swellable polymer in a water/oil emulsion. The polymer particles are dispersed in an oil emulsion wherein the polymer particles are contained within discrete water “droplets” within the oil.
U.S. Pat. No. 5,190,110 discloses the fighting of fires or protection of objects from fire by applying water which comprises dispersing in the water particles of a cross-linked, water-insoluble, but highly water-swellable, acrylic acid derivative polymer in an amount insufficient to bring the viscosity above 100 mPa's.
U.S. Pat. No. 5,849,210 discloses a method of preventing or retarding a combustible object from burning including the steps of mixing water with a super absorbent polymer (“SAP”) to form one at least partially hydrated SAP, and applying the at least partially hydrated SAP to the combustible object, before or after combustion.
U.S. Pat. No. 6,372,842 discloses methods of using an aqueous composition or dispersion containing a water-soluble or water-dispersible synthetic polymer, and compositions formed thereof.
U.S. Pat. No. 5,087,513 discloses polybenzimidazole polymer/superabsorbent polymer particles. These articles are prepared by either mixing the super absorbent polymer particulates with the polybenzimidazole polymer solution during the formation of the polybenzimidazole article, or forming a composite of a polybenzimidazole film or fiber material layer with a super absorbent polymer particulate containing layer. These polybenzimidazole products absorb large amounts of fluid while retaining the flame retardancy and chemical unreactivity of conventional polybenzimidazole materials.
U.S. Pat. No. 4,978,460 discloses a particulate additive for water for firefighting containing a strongly swelling water-insoluble high molecular weight polymer as gelatinizing agent, which comprises a water-soluble release agent which causes the particles of said gelatinizing agent not to swell, the particles of the gelatinizing agent being encased or dispersed in the release agent.
U.S. Pat. No. 5,519,088 discloses an aqueous gel comprising a polymer of (meth)acrylamide or particular (meth)acrylamide derivative(s), particulate metal oxide(s) and an aqueous medium, a process for producing said gel, and products utilizing said gel.
What is needed is a device for attachment to a ladder that provides fire protection to the immediate area around the ladder without affecting the integrity of the ladder.